Rear soft bias dual free layer sensor with patterned decoupling layer

Abstract

Rather than disposing a cap layer on a rear soft bias (RSB) of a DFL read head prior to the patterning of the RSB and TMR sensor, disclosed is a decoupling layer disposed on the RSB and TMR sensor after they undergo patterning, with the decoupling layer undergoing its own subsequent patterning. The RSB and the TMR sensor can thus be patterned (defined) together without a RSB cap layer adversely affecting the patterning. As the decoupling layer undergoes its separate patterning, its cross-track width can be flexibly optimized to be greater than that of both the RSB and the TMR sensor. In some embodiments, the decoupling layer's extra width will help it completely decouple the RSB and TMR sensor from the top shield. The side shields will be partially decoupled from the top shield due to the extra width, but will still retain partial coupling to the top shield.

What is claimed is: 
     
         1 . A dual free layer (DFL) read head, comprising:
 a first shield;   a tunnel magneto resistance (TMR) sensor disposed at a media facing surface (MFS) and over the first shield;   soft bias (SB) side shields disposed adjacent to the TMR sensor, in a cross-track direction and at the MFS, and over the first shield;   a rear soft bias (RSB) disposed adjacent to the TMR sensor in a stripe height direction, and recessed from the MFS and over the first shield;   a decoupling layer disposed on the TMR sensor, the RSB, and at least a portion of the SB side shields, wherein a lower surface of the decoupling layer disposed in contact with the TMR sensor and the SB side shields is co-planar with an uppermost surface of the SB side shields;   a second shield disposed over the decoupling layer and the SB side shields, wherein both the decoupling layer and the SB shields are in contact with the second shield;   a first seed layer having a greater width in the cross-track direction and a greater length in the stripe height direction than the TMR sensor;   an insulating layer disposed between the first seed layer and the RSB; and   a second seed layer disposed between the insulating layer and the RSB.   
     
     
         2 . The DFL read head of  claim 1 , wherein the decoupling layer comprises a non-magnetic, electrically conductive material. 
     
     
         3 . The DFL read head of  claim 2 , wherein the decoupling layer comprises W, Ta, Ru, or combinations thereof. 
     
     
         4 . The DFL read head of  claim 1 , wherein the TMR sensor has a first cross-track direction width at the MFS, the decoupling layer has a second cross-track direction width at the MFS, and wherein the second cross-track direction width is greater than the first cross-track direction width. 
     
     
         5 . The DFL read head of  claim 4 , wherein the RSB has a third cross-track direction width and wherein the first cross-track direction width is substantially equal to the third cross-track direction width. 
     
     
         6 . The DFL read head of  claim 1 , wherein the TMR sensor comprises a capping structure in contact with the decoupling layer. 
     
     
         7 . The DFL read head of  claim 1 , wherein the RSB has a first width, the decoupling layer has a second width at the MFS, and wherein the second width is greater than the first width. 
     
     
         8 . A magnetic recording device comprising the DFL read head of  claim 1 . 
     
     
         9 . A dual free layer (DFL) read head, comprising:
 a tunnel magneto resistance (TMR) sensor disposed at a media facing surface (MFS), wherein the TMR sensor has a first cross-track direction width at the MFS;   soft bias (SB) side shields disposed adjacent to the TMR sensor at the MFS;   insulating material disposed between the TMR sensor and the SB side shields, wherein the TMR sensor, the SB side shields, and the insulating material have a second cross-track direction width at the MFS;   a rear soft bias (RSB) disposed adjacent to the TMR sensor and recessed from the MFS;   a decoupling layer disposed on the TMR sensor, wherein the decoupling layer has a third cross-track direction width at the MFS, wherein the third cross-track direction width is greater than the first cross-track direction width and less than the second cross-track direction width, wherein a lower surface of the decoupling layer disposed in contact with the TMR sensor and the SB side shields is co-planar with an uppermost surface of the SB side shields;   a first seed layer having a greater width in the cross-track direction and a greater length in a stripe height direction than the TMR sensor;   an insulating layer disposed between the first seed layer and the RSB; and   a second seed layer disposed between the insulating layer and the RSB.   
     
     
         10 . The DFL read head of  claim 9 , wherein the decoupling layer is disposed on at least a first portion of the SB side shields. 
     
     
         11 . The DFL read head of  claim 10 , further comprising:
 a first shield, wherein the SB side shields are disposed over the first shield; and   a second shield, wherein at least a second portion of the SB side shields are in contact with the second shield, the first portion being different than the second portion.   
     
     
         12 . The DFL read head of  claim 9 , wherein the decoupling layer is disposed on the RSB. 
     
     
         13 . The DFL read head of  claim 12 , wherein the RSB is spaced from the TMR sensor in the stripe height direction by an insulating material and wherein a shield disposed on the decoupling layer is spaced from the insulating material by the decoupling layer. 
     
     
         14 . A magnetic recording device comprising the DFL read head of  claim 9 . 
     
     
         15 . A dual free layer (DFL) read head, comprising:
 a tunnel magneto resistance (TMR) sensor disposed at a media facing surface (MFS);   soft bias (SB) side shields disposed adjacent to the TMR sensor in a cross-track direction at the MFS;   a rear soft bias (RSB) disposed adjacent to the TMR sensor in a stripe height direction and recessed from the MFS, wherein the RSB has a first width in the cross-track direction;   a decoupling layer disposed on the RSB, wherein the decoupling layer has a second width in the cross-track direction at the MFS, wherein the second width is greater than the first width, wherein a lower surface of the decoupling layer disposed in contact with the TMR sensor and the SB side shields is co-planar with an uppermost surface of the SB side shields;   a first seed layer having a greater width in the cross-track direction and a greater length in the stripe height direction than the TMR sensor;   an insulating layer disposed between the first seed layer and the RSB; and   a second seed layer disposed between the insulating layer and the RSB.   
     
     
         16 . The DFL read head of  claim 15 , wherein the TMR sensor comprises a capping structure, and wherein the decoupling layer is disposed on the capping structure of the TMR sensor. 
     
     
         17 . The DFL read head of  claim 15 , wherein the RSB is spaced from the SB side shields in the cross-track direction by an insulating material, wherein the insulating material has a third width in the cross-track direction, and wherein the first width plus the third width is collectively less than the second width. 
     
     
         18 . The DFL read head of  claim 17 , further comprising a shield, wherein the shield is in contact with the SB side shields and the decoupling layer, and wherein the insulating material is spaced from the shield by the decoupling layer. 
     
     
         19 . The DFL read head of  claim 15 , further comprising a shield, wherein the RSB is not pinned by the shield. 
     
     
         20 . A magnetic recording device comprising the DFL read head of  claim 15 .